Used my January coupon on the final day of the Winter Sale which ended on 1/1, so there was a single day of overlap.
Was able to get Yooka Laylee: The Impossible Lair brand new for only $15.
Needless to say, I'm happy with this new GameStop thing so far. I haven't subscribed to their program in years (mainly because I had Best Buy Gamer Club for 4 years), but this $5 per month thing convinced me to come back to them. Plus, this could just be my local store, but the associates there haven't been really pushy about pre-orders -- something that GameStop as a whole is notorious for badgering people about.
Tried xbox and eshop cards neither worked like everyone said. Tried ps and they worked so got a $10 for $5.
In December I was given a "Thanks for signing up" $5 off code and the store manager forced it to work on eShop credit for me. He also noticed that PSN rang up with no issues for some reason, as you said. Wonder if they'll get that fixed for Xbox and Nintendo cards.